Radiation generator with frustoconical electrode configuration

Abstract

A radiation generator may include an elongate generator housing having a proximal end and a distal end, a target electrode within the elongate generator housing at the distal end thereof, a charged particle source within the elongate generator housing at the proximal end thereof to direct charged particles at the target electrode. A plurality of accelerator electrodes may be spaced apart within the elongate generator housing between the target electrode and the charged particle source to define a charged particle accelerator section. Each accelerator electrode may include an annular portion having a first opening therein, and a frustoconical portion having a base coupled to the first opening of the annular portion and having a second opening so that charged particles from the charged particle source pass through the first and second openings to reach the target electrode.

That which is claimed is: 
     
       1. A radiation generator comprising:
 an elongate generator housing having a proximal end and a distal end; 
 a target electrode within the elongate generator housing at the distal end thereof; 
 a charged particle source within the elongate generator housing at the proximal end thereof to direct charged particles at said target electrode; and 
 a plurality of accelerator electrodes spaced apart within the elongate generator housing between the target electrode and the charged particle source to define a charged particle accelerator section, each accelerator electrode comprising
 an annular portion having a first opening therein, and 
 a frustoconical portion having a base coupled to the first opening of the annular portion and having a second opening so that charged particles from the charged particle source pass through the first opening and the second opening to reach the target electrode. 
 
 
     
     
       2. The radiation generator of  claim 1 , wherein said frustoconical portion comprises an included angle in a range of 10° to 80°. 
     
     
       3. The radiation generator of  claim 1 , wherein the plurality of accelerator electrodes comprise a first accelerator electrode and a second accelerator electrode, wherein the first accelerator electrode having a respective frustoconical portion with a first included angle, and wherein the second accelerator electrode having a respective frustoconical portion with a second included angle different from the first included angle. 
     
     
       4. The radiation generator of  claim 1 , wherein said annular portions of said plurality of accelerator electrodes face said target electrode. 
     
     
       5. The radiation generator of  claim 1 , wherein said charged particle source comprises an electron stream generator. 
     
     
       6. The radiation generator of  claim 1 , wherein said charged particle source comprises an ion stream generator. 
     
     
       7. The radiation generator of  claim 1 , further comprising an insulator carried along a sidewall of said elongate generator housing. 
     
     
       8. A well logging tool comprising:
 a sonde housing; 
 at least one radiation detector carried by said sonde housing; and 
 a radiation generator carried by said sonde housing and comprising:
 an elongate generator housing having a proximal end and a distal end, 
 a target electrode within the elongate generator housing at the distal end thereof, 
 a charged particle source within the elongate generator housing at the proximal end thereof to direct charged particles at said target electrode, and 
 a plurality of accelerator electrodes spaced apart within the elongate generator housing between the target electrode and the charged particle source to define a charged particle accelerator section, each accelerator electrode comprising:
 an annular portion having a first opening therein, and 
 a frustoconical portion having a base coupled to the first opening of the annular portion and having a second opening so that charged particles from the charged particle source pass through the first opening and the second opening to reach the target electrode. 
 
 
 
     
     
       9. The well logging tool of  claim 8 , wherein said frustoconical portion comprises an included angle in a range of 10° to 80°. 
     
     
       10. The well logging tool of  claim 8 , wherein the plurality of accelerator electrodes comprise a first accelerator electrode and a second accelerator electrode, wherein the first accelerator electrode having a respective frustoconical portion with a first included angle, and wherein the second accelerator electrode having a respective frustoconical portion with a second included angle different from the first include angle. 
     
     
       11. The well logging tool of  claim 8 , wherein said annular portions of said plurality of accelerator electrodes face said target electrode. 
     
     
       12. The well logging tool of  claim 8 , wherein said charged particle source comprises an electron stream generator. 
     
     
       13. The well logging tool of  claim 8 , wherein said charged particle source comprises an ion stream generator. 
     
     
       14. The well logging tool of  claim 8 , further comprising an insulator carried along a sidewall of said elongate generator housing. 
     
     
       15. A method for making a radiation generator comprising:
 positioning a target electrode within an elongate generator housing at a distal end thereof; 
 and positioning a charged particle source within the elongate generator housing at a proximal end thereof to direct charged particles at the target electrode; and 
 positioning a plurality of accelerator electrodes within the elongate generator housing between the target electrode and the charged particle source and spaced apart from one another to define a charged particle accelerator section, each accelerator electrode comprising:
 an annular portion having a first opening therein, and 
 a frustoconical portion having a base coupled to the first opening of the annular portion and having a second opening so that charged particles from the charged particle source pass through the first opening and the second opening to reach the target electrode. 
 
 
     
     
       16. The method of  claim 15 , wherein the frustoconical portion comprises an included angle in a range of 10° to 80°. 
     
     
       17. The method of  claim 15 , wherein the plurality of accelerator electrodes comprise a first accelerator electrode and a second accelerator electrode, wherein the first accelerator electrode having a respective frustoconical portion with a first included angle, and wherein the second accelerator electrode having a respective frustoconical portion with a second included angle different from the first include angle. 
     
     
       18. The method of  claim 15 , wherein the annular portions of the plurality of electrodes face the target electrode. 
     
     
       19. The method of  claim 15 , wherein the charged particle source comprises an electron stream generator. 
     
     
       20. The method of  claim 15 , wherein the charged particle source comprises an ion stream generator.